Additive manufacturing, also known as 3-D printing and rapid prototyping, is the process of extruding plastic material through a nozzle to form three dimensional models. The models formed by additive manufacturing may be used for functional prototype testing, reviewing fit and function of physical parts, and/or in low volume production scenarios. Additive manufacturing allows for the quick manufacture of physical parts while also reducing cost by eliminating the need for expensive tooling and/or processes that would otherwise be needed to manufacture the parts.
Another benefit of additive manufacturing is the ability to extrude a variety of different plastic materials. The ability to extrude many different plastic materials allows for the selection of plastic based on the physical and/or mechanical properties of the plastic material. Yet another benefit of additive manufacturing is the ability to extrude the plastic material through a variety of different nozzles. The ability to use different nozzles allows physical models to he created at a slower rate with greater detail using a smaller nozzle, or the physical models can be created at a faster rate with less detail using a larger nozzle.
Traditionally, additive manufacturing machines have been equipped with a single nozzle. More recent additive manufacturing machines are being provided with two or more nozzles. The additional nozzles provided the benefit of being able to continuously manufacture a physical part utilizing different plastic materials and/or nozzles without having to interrupt operation of the machine to change out the plastic material and/or nozzle.
The existence of more than one nozzle presents a problem in that each of the nozzles must be elevated the exact same distance over the platform on which the physical part is manufactured in order to ensure accurate manufacture of the physical part. However, elevating all of the nozzles at the same distance creates the risk of one or more of the nozzles coming into contact with the physical part, thereby damaging the part being manufactured.
Current solutions for the above noted difficulty are problematic in that the current solutions undesirably add cost and complexity to the additive manufacturing machine.